1. Field of the Invention
The present invention relates generally to a bushing having an eccentric bore for adjusting the caster and/or camber in a steering structure of a front or four wheel drive vehicle, and to a method of setting the camber and caster of the vehicle steering structure using the bushing of the present invention.
2. Description of the Prior Art
Various bushings having an eccentric bore have been used to adjust camber and caster in the steering structures of front or four wheel drive vehicles. These steering structures typically include a yoke carried at an end of a front axle of the vehicle. At least one arm of the yoke has an opening for receiving the bushing. A wheel spindle assembly is pivotally mounted on the yoke by ball joints having a stud extending through the opening in the yoke arm, in locking engagement with the bushing. The orientation of the bushing within the opening determines how far the wheel spindle assembly will be shifted away or towards the axle to correct camber, and/or forward or rearward laterally of the axle to correct caster.
With most prior art bushings, the bushings are driven into the opening in the yoke, with the stud of the ball joint extending through the eccentric bore of the housing. Readings of caster and camber are taken as the bushing is rotated until the bushing orientation provides the desired caster and camber. The ball joint and bushing are then secured in place on the yoke. Indicative of this type of assembly is U.S. Pat. No. 4,400,007 to Ingalls. Once the Ingalls bushing is properly positioned, a lock ring is coincidentally fixed to the bushing and positioning lugs carried by the yoke to secure the bushing in place.
U.S. Pat. No. 4,232,880 to Dickerson et al describes an eccentric bushing having an axially offset bore; that is, the axis of the bore is offset with respect to the axis of the outer surface of the bushing. The Dickerson et al bushing has an integral collar which facilitates manual grasping and rotation of the bushing to adjust the camber and caster of the wheel assembly. Other patents indicative of this arrangement include U.S. Pat. No. 4,026,578 to Mattson, U.S. Pat. No. 2,859,058 to Traugott, and U.S. Pat. No. 3,163,441 to Traugott.
U.S. Pat. No. 4,252,338 to Ingalls et al describes an externally threaded bushing threaded into an internally threaded bore defined in a yoke.
All of the art described above require a trial and error method of adjusting camber and caster, which is time-consuming.
U.S. Pat. No. 2,923,555 to Kost et al describes an externally threaded bearing having an eccentric bore. The bearing is dimensioned to be threaded into an internally threaded bore of a yoke. A precalibrated removable scale is attached to the yoke adjacent the internally threaded bore and serves as a caster and camber guide with reference to which the bearing is rotatively adjusted. Most yokes are not equipped with such scales.
An Ingalls Catalog No. 840 discloses an adjustable bushing including an inner sleeve having an eccentric bore, rotably mounted within an eccentric bore of an outer sleeve. Precalibrated scales are fixed to the outer surface of each sleeve. The camber and caster provided by the bushing is set by rotating the inner sleeve with respect to the outer sleeve until selected reference symbols on each scale are aligned. Both sleeves must be circumferentially expanded, by drawing a tapered shaft of a ball joint through the inner sleeve bore, to secure the bushing in place on the yoke.